Canon EF-S 55-250mm f/4-5.6 IS STM

SLRgear Review
October 21, 2014
by Andrew Alexander

Canon released the latest version of its 55-250mm kit lens at the end of 2013, marking the third iteration of the product. However it's not a replacement for the 55-250mm EF-S IS II, as both are still available for sale. Notable improvements include incorporating the new STM stepping motor autofocus system, for near-silent and fly-by-wire focusing; as well, internal focusing has been added, which means the lens now has full-time manual override for focusing. The lens also has a newly designed high speed CPU, improved AF algorithm and rear focusing.

The 55-250mm isn't a ''constant'' lens, in that as you increase the focal length, both the minimum and maximum aperture sizes decrease. The following table reflects the change in aperture size with focal length:

The Canon 55-250mm ƒ/4-5.6 does not ship with a lens hood; an optional circular-style lens hood is available separately. The lens takes 58mm filters, and is available for $300.

Sharpness
The 55-250mm ƒ/4-5.6 is impressively sharp for a ''kit'' lens, even when set to its widest apertures. Canon has definitely improved upon its previous 55-250mm offerings, where there was some corner softness at its widest apertures; with the STM version of the 55-250mm, it's super-sharp, even when used wide open.

With an exception, of course -- provided you use the lens below the 200mm focal length. At 200mm and above, the lens starts out with some prominent corner softness at ƒ/5.6, and stopping down doesn't actually improve image quality, unfortunately.

Image quality becomes softer at ƒ/16 with the introduction of diffraction limiting. Results at ƒ/22 are acceptable, but anything smaller than that and the image becomes quite soft indeed.

Chromatic Aberration
The Canon EF-S 55-250 ƒ/4-5.6 IS STM has some small issues with chromatic aberration, but nothing like we've seen in other lenses in this price point. Generally, you get your best performance in the mid-range of the lens -- anything over the 55mm point and below 200mm. Outside of this, you'll note some color bleed in the corners, in areas of contrast; in particular, magenta-green fringing.

Shading (''Vignetting'')
At any focal length with an aperture setting below ƒ/8, we note some level of corner shading, but not an extreme amount (it's fairly typical of lenses in this category). The worst is seen at the 250mm setting at ƒ/5.6, where the extreme edges of the image will be about two-thirds of a stop darker than the center of the image.

Distortion
As with the previous iteration of this lens, distortion is handled very well across the impressive zoom range. The 55-250mm produces a distortion profile which is fairly typical for this class of lens; barrel-distortion at the wide end (55mm), with increasing pincushion distortion as the lens is set to a larger focal length. Barrel distortion isn't a big issue: 0.5% maximum corner distortion at 55mm. This distortion is fairly linear until there is effectively no distortion at 100mm, and is easily corrected in image post-processing.

The story changes after 100mm, where average distortion retains its barrel character, but maximum distortion is visible in the corners as pincushion distortion. At its most visible there is -0.25% pincushion distortion at 250mm in the corners. This style of distortion is a bit more difficult to correct in post-processing.

Autofocus Operation
The Canon EF-S 55-250 ƒ/4-5.6 IS STM employs an autofocus system called a "Stepping Motor," which allows the lens to provide smooth and quiet autofocus operation, particularly during video capture. The lens took well under a second to focus from infinity to close-focus. The lens offers full-time manual operation, a difference from the previous model. You can override autofocus results at any time by just turning the focus ring. Attached 58mm filters will not rotate during focus operations, making life easier for polarizer users.

Macro
With a minimum close-focus range of 85cm (2' 8") and a magnification ratio of 0.29x, the 55-250mm provides respectable performance in the macro category.

Build Quality and Handling
At just over 13 ounces, the Canon EF-S 55-250mm ƒ/4-5.6 IS STM makes a light package for the versatile range of focal lengths it offers. To accomplish this the lens is largely plastic, though it is of a high-quality construction. Both the lens mount and the 58mm filter threads are plastic. There is no flexing or rattling when using the lens: the exterior of the lens has a spatter-painted appearance, while the lens barrel, visible when the lens extends towards 250mm, is smooth. The only information available on the lens are marked focal lengths: there are no distance scales or depth-of-field indicators.

The lens design consists of 15 elements in 12 groups, with 1 UD element. The aperture is made up of seven curved diaphragm blades to produce pleasing a out-of-focus background. The lens only has two switches to speak of: one to enable or disable autofocus (''AF/MF'') and one to activate or deactivate image stabilization (''Stabilizer ON/OFF''). There is a very slight sound when image stabilization is active, but mostly only audible when your ear is next to the lens.

The prominent zoom ring, taking up half the lens body, takes a half-turn to go through its entire range of focal lengths. The ring is fairly stiff and resistant to zoom creep. The design of the lens is such that as the lens extends its focal length the barrel physically extends, adding a further 1 3/4'' to the overall length at 250mm.

The half-inch-wide focusing ring is mounted near the front of the lens, with a plastic ridged knurl that is easy to turn. With the new STM focusing system, the lens focuses electrically, meaning there is no direct mechanical connection between turning the ring and the resulting focus. The focusing ring will turn forever in either direction, and offers a good amount of resistance for manual focus.

One of the advantages of this lens is its image stabilization feature, which works very well for this lens. Check out our IS Test tab above to see our results.

The optional ET-63 circular lens hood is available for the lens at around $30.

Alternatives

Sigma and Tamron used to market competitors in the 55-200mm range, but these products have since been discontinued.

Canon EF-S 55-250mm ƒ/4-5.6 IS II ~$250
At the time of writing, you can still pick up the previous version of the 55-250mm lens, which is still very good. You'll want it if primarily if you're a purist who doesn't believe in fly-by-wire focusing. Otherwise, the new lens is better in almost all respects.

Sigma 50-200mm ƒ/4-5.6 DC OS HSM ~$?
It's been discontinued, but if you're determined to save money on a lens in this category, this would be where went - the lens features Sigma's OS stabilization technology, but in the end wasn't great optically.

Conclusion
Canon has updated this lens well, primarily in the focusing category with both internal focusing and the STM motor. The pricing hasn't changed much, so if you're looking for a good telephoto addition to your bag, you really can't go wrong here.

Product Photos

Sample Photos

Click here for Real-world Gallery Images on our Flickr page!

The VFA target should give you a good idea of sharpness in the center and corners, as well as some idea of the extent of barrel or pincushion distortion and chromatic aberration, while the Still Life subject may help in judging contrast and color. We shoot both images using the default JPEG settings and manual white balance of our test bodies, so the images should be quite consistent from lens to lens.

Still Life shot

VFA target

As appropriate, we shoot these with both full-frame and sub-frame bodies, at a range of focal lengths, and at both maximum aperture and ƒ/8. For the ''VFA'' target (the viewfinder accuracy target from Imaging Resource), we also provide sample crops from the center and upper-left corner of each shot, so you can quickly get a sense of relative sharpness, without having to download and inspect the full-res images. To avoid space limitations with the layout of our review pages, indexes to the test shots launch in separate windows.